This SBIR phase II application proposes to develop a human physiology simulator for use at all levels of medical and nursing education. The simulator will describe normal or abnormal physiology in a surrogate patient, so that physiologic experiments can be performed and unknown medical cases can be embedded in the program for use as diagnostic and therapeutic challenges. This surrogate patient differs from conventional medical education aids by using real-time solution of model equations to predict behavior, rather than implementing "programmed-text" systems for leading students through paths planned by the authors. In phase I, the specific aims were met and exceeded, and Critical Concepts produced a prototype program (SimBioSys version 1.0) that is ready for use in teaching physiology to medical students. SimBioSys incorporates the heart, lungs, kidneys, and reflex control, in a framework that is user- friendly and reliable enough for distribution, while providing a flexible and stable architecture for further development. Technical feasibility having thus been demonstrated, this phase II application proposes to complete the project, by producing a medically and physiologically realistic patient simulator with even more detailed modeling and extensive online support. Critical Concepts will (1) enhance the current physiologic simulation and incorporate electrocardiographic signals and spontaneous respiration, (2) enhance the medical interface to the simulator, (3) document the system, (4) develop hooks for multimedia enhancements, (5) evaluate the realism and educational efficacy of simulator use, and (6) plan and investigate the Phase III port to other platforms.